1. Technical Field
This invention relates to Seismic base isolation and energy dissipation devices for structures. The present invention will be placed between a structural load and its foundation.
2. Background Art
Many devices and equipment systems exist to reduce the seismic ground motion energy that is transmitted to a structure when an earthquake event occurs. Many of these earthquake motion protective systems fall in the category of base or foundation isolation systems, as does the present invention. Some of the most complex units are those that reply on pendulum like motion where gravity supplies the force to dampen the energy and restore the supported load to its original point of equilibrium and stability. A common draw back of most prior art of these base isolation systems are they are very expensive and complex. Also these systems require uncommon and difficult to manufacture materials and some require advanced technologies in the fields of electronics, computers and hydraulics. Yet another drawback is many only allow movement in two perpendicular directions. Many of these pendulum systems require constant monitoring and are costly to maintain or need replacement after a seismic event. The engineers designing the older pendulum systems often focus all the seismic energy on to a few pivotal moving parts creating a lot of stress on these complex parts, making it very hard to predict their reliability or extend their application to support larger structures, also limiting the amount of ground movement they could handle. The present invention overcomes many of these drawbacks by introducing a new design that will not focus the seismic motion to a few unique and often over loaded parts. The present invention will scale easily to support large size structural load while remaining the same design or shape, except for using thicker materials and greater dimensions to accommodate larger loads. The present invention will reduce or prevent structural damage and it will eliminate all the previously cited short comings of high cost and mechanical complexity, and limited range of applications also the present invention will be easy to assembly, easy to install and will require very little maintenance.
3. Description Prior Art
A protective system for seismic base isolation and energy dissipation is well known and has many design configurations; most of the prior art of invention for earthquake base isolation systems are very expensive and of complex design. They often require-special materials also they are hard to manufacture. Most do not scale up easily and they usually require constant maintenance. Many are difficult to re-engineer or provide options for other applications. Most need to be refurbished or replaced after a quake event and they have limited ground displacement range. Many are very limited in there ability to dissipate seismic energy and most do not have energy damping options. Many do not accommodate all three axis of movement and lastly most focuses all the quake displacement energy in to a few pivotal parts.
For example U.S. Pat. No. 6,725,612 B2 issued Apr. 27, 2004 to Kim. This system uses a multi layer assembly of bi-directional rollers placed on a upper and a lower curved guide rail that is set at right angles to each other and are designed to roll in a pendulum like motion. This system is expensive, complex and has many unique specialized parts, also this system not easy to create and will not scale up to handle very large structures, it also will require maintenance, to continue this system is more difficult to engineer. This system will need to be refurbished after quake events also this system can not handle large ground displacement or dissipate very much seismic energy. This system has no stated solution for a vertical displacement event and very limited energy damping. This pendulum like system seems to focus all the immense energy coming from a seismic event in to a few pivotal moving parts creating huge stresses making it very difficult to have long term reliability.
Another example is U.S. Pat. No. 6,966,154 B1 issued Nov. 22, 2005 to Bierwirth. This system uses an arrangement of Virtual Pendulums called Quakeprotect modules. The goal is to suspend the entire building structure from long rods allowing the structure to sway gently in an earthquake. The claim is that this system can provide protection even in the maximum possible magnitude of earthquake. This system is expensive, complex and has many unique specialized parts, also this system not easy to create and will not scale up to handle very large structures, it also will require maintenance, to continue this system is more difficult to engineer. This system will need to be refurbished after quake events also this system does claim to handle large ground displacement and dissipate seismic energy. This system has no stated solution for a vertical displacement event and very limited energy damping. This pendulum like system seems to focus all the immense energy coming from a seismic event in to a few pivotal moving parts creating huge stresses making it very difficult to have long term reliability.
Another example is U.S. Pat. No. 6,948,284 B2 issued Sep. 27, 2005 to Chiang. This system claims an all directional damping and earthquake resisting unit comprising multiple balls that will roll inside this assembly having at least one inner-upper carrier and at least one inner-lower carrier with a surface of wavy convexes and concaves to absorb earthquake energy. This system requires computer controlled guidance to manage a piston assembly that will direct the rolling balls, it also has attenuator valve, power cylinders and pumps. This system is expensive, very complex and has many unique specialized parts, also this system not easy to create and will not scale up to handle very large structures, it also will require maintenance, to continue this system is more difficult to engineer. This system will need to be refurbished after quake events also this system can not handle large ground displacement or dissipate very much seismic energy. This system has no stated solution for a vertical displacement event and claims some energy damping. This pendulum like system seems to focus all the immense energy coming from a seismic event in to a few pivotal moving parts creating huge stresses making it very difficult to have long term reliability.
Another example is U.S. Pat. No. 6,862,849 B2 issued Mar. 8, 2005 to Kim. This system uses a bi-directional sliding pendulum like channels and articulated sliding channeled assemblies that attach to a structure. This system is expensive, complex and has many unique specialized parts, also this system not easy to create and will not scale up to handle very large structures, it also will require maintenance, to continue this system is more difficult to engineer. This system will need to be refurbished after quake events also this system can not handle large ground displacement or dissipate very much seismic energy. This system has no stated solution for a vertical displacement event and very limited energy damping. This pendulum like system seems to focus all the immense energy coming from a seismic event in to a few pivotal moving parts creating huge stresses making it very difficult to have long term reliability.
Yet another example is U.S. Pat. No. 6,164,022 issued Dec. 12, 2000 to Ishikawa et al. This system uses a three-dimensional guiding curved track rail apparatus on the bottom and on the top half, mounted at right angles. The connecting assembly has many parts including roller cylinders. This system is expensive, very complex and has many unique specialized parts, also this system not easy to create and will not scale up to handle very large structures, it also will require maintenance, to continue this system is more difficult to engineer. This system will need to be refurbished after quake events also this system can not handle large ground displacement or dissipate very much seismic energy. This system has no stated solution for a vertical displacement event and very limited energy damping. This pendulum like system seems to focus all the immense energy coming from a seismic event in to a few pivotal moving parts creating huge stresses making it very difficult to have long term reliability.
Another example is U.S. Pat. No. 6,820,380 B2 issued Nov. 23, 2004 to Chong-Shien Tsai In this system one contact surface between two slide block members with spheroid coupling bearing nested between upper and lower block members. This system is expensive, very complex and has many unique specialized parts, also this system not easy to create and will not scale up to handle very large structures, it also will require maintenance, to continue this system is more difficult to engineer. This system will need to be refurbished after quake events also this system can not handle large ground displacement or dissipate very much seismic energy. This system has no stated solution for a vertical displacement event and very limited energy damping. This pendulum like system seems to focus all the immense energy coming from a seismic event in to a few pivotal moving parts creating huge stresses making it very difficult to have long term reliability.
Another example is U.S. Pat. No. 6,385,917 issued May 14, 2002 to Masashi Konomoto The base isolation device with rail tracks disposed orthogonally to each other where a rotary sleeve and damping chamber filled with a viscous fluid. This system is expensive, very complex and has many unique specialized parts, also this system not easy to create and will not scale up to handle very large structures, it also will require maintenance, to continue this system is more difficult to engineer. This system will need to be refurbished after quake events also this system can not handle large ground displacement or dissipate very much seismic energy. This system has no stated solution for a vertical displacement event and has some limited energy damping. This pendulum like system seems to focus all the immense energy coming from a seismic event in to a few pivotal moving parts creating huge stresses making it very difficult to have long term reliability.
Another example is U.S. Pat. No. 7,409,799 B2 issued Aug. 12, 2008 to Tsai. This device has a top plate and base plate in between is the adapter with curved rails and rolling shafts placed at right angles. This system is expensive, complex and has many unique specialized parts, also this system not easy to create and will not scale up to handle very large structures, it also will require maintenance, to continue this system is more difficult to engineer. This system will need to be refurbished after quake events also this system can not handle large ground displacement or dissipate very much seismic energy. This system has no stated solution for a vertical displacement event and very limited energy damping. This pendulum like system seems to focus all the immense energy coming from a seismic event in to a few pivotal moving parts creating huge stresses making it very difficult to have long term reliability.
Another example is U.S. Pat. No. 7,472,518 B2 issued Jan.6, 2009 to Chong-Shien Tsai. This device has a sliding members mounted in two layers in between is two slotted seats with curved in opposites directions and rolling shafts placed at right angles and a dampening layer. This system is expensive, complex and has many unique specialized parts, also this system not easy to create and will not scale up to handle very large structures, it also will require maintenance, to continue this system is more difficult to engineer. This system will need to be refurbished after quake events also this system can not handle large ground displacement or dissipate very much seismic energy. This system has no stated solution for a vertical displacement event and very limited energy damping. This pendulum like system seems to focus all the immense energy coming from a seismic event in to a few pivotal moving parts creating huge stresses making it very difficult to have long term reliability.
Another example is U.S. Pat. No. 6,126,136 issued Oct. 3, 2000 to Yen et al. A passive vibration system with a protruding lug fitting in rubber snugly also two convex curved surface that will slide with wear-resistant resin layers. This system is expensive, complex and has many unique specialized parts, also this system not easy to create and will not scale up to handle very large structures, it also will require maintenance, to continue this system is more difficult to engineer. This system will need to be refurbished after quake events also this system can not handle large ground displacement or dissipate very much seismic energy. This system has no stated solution for a vertical displacement event and very limited energy damping. This pendulum like system seems to focus all the immense energy coming from a seismic event in to a few pivotal moving parts creating huge stresses making it very difficult to have long term reliability.